re PR c++/81054 (ICE with volatile variable in constexpr function)

/cp
2018-01-17  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/81054
	* constexpr.c (ensure_literal_type_for_constexpr_object): Return
	error_mark_node when we give an error.
	* decl.c (cp_finish_decl): Use the latter.

/testsuite
2018-01-17  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/81054
	* g++.dg/cpp0x/constexpr-ice19.C: New.

From-SVN: r256816

gcc/cp/ChangeLog

+2018-01-17  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/81054
+	* constexpr.c (ensure_literal_type_for_constexpr_object): Return
+	error_mark_node when we give an error.
+	* decl.c (cp_finish_decl): Use the latter.
+
 2018-01-17  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/83287

gcc/cp/constexpr.c

@@ -75,7 +75,8 @@ literal_type_p (tree t)
 }
 
 /* If DECL is a variable declared `constexpr', require its type
-   be literal.  Return the DECL if OK, otherwise NULL.  */
+   be literal.  Return error_mark_node if we give an error, the
+   DECL otherwise.  */
 
 tree
 ensure_literal_type_for_constexpr_object (tree decl)
@@ -97,6 +98,7 @@ ensure_literal_type_for_constexpr_object (tree decl)
 	      error ("the type %qT of %<constexpr%> variable %qD "
 		     "is not literal", type, decl);
 	      explain_non_literal_class (type);
+	      decl = error_mark_node;
 	    }
 	  else
 	    {
@@ -105,10 +107,10 @@ ensure_literal_type_for_constexpr_object (tree decl)
 		  error ("variable %qD of non-literal type %qT in %<constexpr%> "
 			 "function", decl, type);
 		  explain_non_literal_class (type);
+		  decl = error_mark_node;
 		}
 	      cp_function_chain->invalid_constexpr = true;
 	    }
-	  return NULL;
 	}
     }
   return decl;

gcc/cp/decl.c

@@ -6810,8 +6810,12 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
       cp_apply_type_quals_to_decl (cp_type_quals (type), decl);
     }
 
-  if (!ensure_literal_type_for_constexpr_object (decl))
-    DECL_DECLARED_CONSTEXPR_P (decl) = 0;
+  if (ensure_literal_type_for_constexpr_object (decl)
+      == error_mark_node)
+    {
+      DECL_DECLARED_CONSTEXPR_P (decl) = 0;
+      return;
+    }
 
   if (VAR_P (decl)
       && DECL_CLASS_SCOPE_P (decl)

gcc/testsuite/g++.dg/cpp0x/constexpr-ice19.C

+// PR c++/81054
+// { dg-do compile { target c++11 } }
+
+struct A
+{
+  volatile int i;
+  constexpr A() : i() {}
+};
+
+struct B
+{
+  static constexpr A a {};  // { dg-error "not literal" }
+};